Method of increasing the likelihood of precipitation by the artificial introduction of sea water vapor into the atmosphere windward of an air lift region

ABSTRACT

The invention pertains to a method of producing fresh water utilizing modification of air mass conditions by injecting sea water into solar-heated air to evaporate sea water into the atmosphere and increase the air water vapor content, and thereby greatly increase the capacity of the so modified air mass for absorbing the available radiant energy for warming the air by solar and terrestial radiant energy to increase the ability of the air to absorb increased quantities of water vapor and ambient temperature, and thereafter lift the treated air to sufficient altitudes to produce convective instability, cumuliform clouds and precipitation. Preferably, the injection of sea water into the atmosphere, and the solar heating thereof, occur at alternate land areas disposed windwardly of a mountain or other natural orographic barrier wherein the treated air is lifted orographically.

United States Patent [72] Inventor Orval R. Feather 2464 Bunker Hill,Ann Arbor, Mich. 48105 [2]] Appl. No. 819,625 [22] Filed Apr. 28, I969[45] Patented Aug. 24, I971 [54] METHOD OF INCREASING THE LIKELIHOOD OFPRECIPITATION BY THE ARTIFICIAL INTRODUCTION OF SEA WATER VAPOR INTO THEATMOSPHERE WINDWARD OF AN AIR LIFT REGION 7 Claims, 3 Drawing Figs.

[52] 0.8. CI 239/2, 239/14 [51] lnt.Cl A0lg 15/00 [50] Field ofSearch239/2, 14

[56] Reference Cited UNITED STATES PATENTS 3,l35,466 6/1964 Reid 239/2X3,409,220 11/1968 Black ABSTRACT: The invention pertains to a method ofproducing fresh water utilizing modification of air mass conditions byinjecting sea water into solar-heated air to evaporate sea water intothe atmosphere and increase the air water vapor content, and therebygreatly increase the capacity of the so modified air mass for absorbingthe available radiant energy for warming the air by solar and terrcstialradiant energy to increase the ability of the air to absorb increasedquantities of water vapor and ambient temperature, and thereafter liftthe treated air to sufficient altitudes to produce convectiveinstability, cumuliform clouds and precipitation. Preferably, theinjection of sea water into the atmosphere, and the solar heatingthereof, occur at alternate land areas disposed windwardly of a mountainor other natural orographic barrier wherein the treated air is liftedorographically'.

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BACKGROUND OF THE INVENTION The invention pertains to the art ofmodifying weather by the forced evaporation of sea water into the air,and recovering fresh water therefrom by inducing precipitation.

It has been previously proposed to increase the likelihood ofprecipitation by injecting sea or fresh water into the air that themoisture content of the air be increased. US Pat. Nos. 2,776,167 and3,135,466 are directed to apparatus of this type. However, the mereconcept of injecting moisture into the air in order to increase thelikelihood of precipitation is not likely to meet with success in thatthere are a number of meteorological parameters and characteristicswhich, in combination, need to be present before the desiredprecipitation will occur. One important air mass property, convectiveinstability, is a recognized prerequisite to inducing convectiveprecipitation. Convective instability cannot occur unless somesatisfactory means for increasing the equivalent potential temperatureof one air mass over that of a surrounding air mass is achieved. Thenovel technique proposed herein provides the means for selectivelyincreasing the equivalent potential temperature of one air mass relativeto the air mass surrounding the first air mass. None of the prior artprovides the means for so increasing the equivalent potentialtemperature of an air mass by reason of the fact that the evaporationprocess is characteristically a constant equivalent potentialtemperature or isentropic process. Also, the location of the desiredprecipitation inmethods and systems proposed by the prior art is notreadily predictable, and it is possible that rainfall if so produced,would fall at locations which were not particularly in need of water,

The conditions required to produce rain are characteristically verycomplicated and not yet fully understood even by meteorological experts.However, it is known that certain basic conditions need not to bepresent, and with the apparatus and methods of the prior art the ratherhaphazard introduction of water vapor, even over vast areas, into theatmosphere has not resulted in weather modification that can be readilyutilized in a beneficial manner. For instance, in previous attempts toproduce weather modification by introducing water into the air, thelocation of the water introduction could not be so located near a sourceof orographic lift whereby maximum utilization of the water vapor ladenair could be achieved.

In order to induce precipitation by injecting moisture into the air toincrease the water vapor content thereof, it is also necessary to havecertain conditions present to accompany the introduction of water vaporinto the atmosphere. For in stance, sufficient solar heat is necessaryas the prime source of energy required wherein sufficient solar heat isavailable to raise the moisture absorption level of the atmosphere intowhich the sea water is being introduced. Also, it is necessary thatcertain prevailing wind characteristics be present wherein the windpredominately moves in a given direction at a relatively low windvelocity. High wind velocities could cause sufficient moisturedisbursement and diffusion as to negate the desired increase in moisturecontent of the atmosphere resulting from the injecting of moisture intothe air. Also, a relatively high level of natural water vapor contentshould exist, though not critically necessary, in the air and thetemperatures ofthe land over which the air is moving and air into whichthe water injection is occurring should be relatively high to optimizethermodynamic air mass properties for producing a markedly divergentangle between the dry and the saturated adiabatic lapse rates of thepseudoadiabatic energy diagram.

Another most important factor with respect to producing a successfulweather modification program wherein the introduction of water vaporinto the air by artificial means is 2 required lies with the powerrequirement for introducing the water into the air. With the prior artdevices it is intended that pumps, fans and the like be used to forcethe water into the air. In that it is necessary to introduce the watervapor into the air over a substantially large area, the powerrequirement, if manmade power is to be used, is tremendous, and is sogreat as to make successful weather modification programs using manmadepower systems prohibitively expensive.

SUMMARY OF THE INVENTION It is the purpose of the invention to provide apredesigned weather modification system, wherein fresh water may beobtained by precipitation, which includes the forced evaporation of seawater into the atmosphere to the maximum radiant energy absorption rateavailable'and inducing the precipitation of fresh water from theatmosphere at a predetermined location. in the practice of the inventionit is necessary that certain physical and natural requirements be metfor the practice of the invention to become practical, and while thepractice of the invention is not possible in all parts of the earth, forexample in polar regions, there are a number of locations upon the earthwherein increased amounts of fresh water are urgently required, andwherein the requirements concerning geographical features and sufficientsolar radiant energy flux densities are available.

Basically, the practice of the invention employs the use of existingsolar energy in desert and other similar high solar energy regions forthe evaporation of sea water forced sprayed from the earths surface intothe lower boundary layer of the atmosphere. The evaporated moistureretained by the lower atmosphere is transported by prevailing winds to anearby mountain range, where it is orographically lifted and the desiredwater released as precipitation from resulting cumu' lous clouds andthunderstorms.

in order to be most effective, the introduction of the sea water intothe air occurs at a plurality of spaced areas windward of the mountainrange which provides the orographic lift. Alternating spray regions atwhich the sea water is introduced into the air and nonspraying regionsare required wherein the air may be heated by solar and terrestialradiant energy to thereby increase the airs ability to absorb and retainadditional water vapor such that a progressively increasing ability ofthe air to carry moisture occurs. For instance, alternate spraying bandregions and nonspraying band regions of approximately 1 mile in width,though the two bands may be-designed to be of different widths, may belocated windward of the mountain range, and by using eight or 10spraying and nonspraying regions, a progressive and incremental waterabsorption and heat absorption by the air occurs as the air movestowards the mountain or orographic lift elevation. The length of theband regions will be primarily determined by the shape and size of themountain range available, and the bands will be located in a parallel orconcentric" relationship with each other and the available mountains.

Of course, a considerable amount of sea water must be sprayed into theair in order for the practice of the method to be fully utilized. Tomechanically pump such amounts of water into the air would require agreat deal of power, and for this reason the practice of the inventionis most practical in those land areas which are significantly below sealevel wherein water may be brought into the region in which theinvention is to be practiced by aquaducts, pipelines or channels, andgravity is utilizedto produce the desired water pressure for introducingthe sea water into the air. In those regions where the land areas inwhich spraying occurs are significantly below sea level, such as morethan or 200 feet below sea level, greater water pressures than areabsolutely necessary for spraying purposes would be available, and it isenvisioned that hydroelectric power plants would be located as toutilize the hydraulic head available for producing large quantities ofelectric power. in that the practice of the invention will producesea-salt residue, the presence of this residue, and the availability ofcheap electric energy, will permit the production of chemicals andfertilizers using the constituents of seasalt residue which may beelectrically processed.

Additionally, it is necessary that the land region be such that clearskies of arid or other high-insolation local areas exist for providingsolar heat of sufficient amounts to furnish the sufficient energy baseto heat the air into which the moisture is and has been introduced.Another requirement for the region in which the invention is practicedis that there must be a relatively low characteristic prevailing windtoward the mountain range. Preferably, a prevailing wind between 5 andmiles an hour below the 3,000 to 5,000 feet altitude should beavailable, and in the higher atmospheric levels to 10,000 feet theprevailing wind velocity could be substantially higher.

It is also helpful, though not critically necessary, in the practice ofthe invention that an average quantity of natural water vapor contentexist in the upper atmosphere above the arid region in order to providemoisture sustenance needed for sustained shower activity over anexpanded period of time and to reduce the amount of water vapor that hasto be introduced to the lower levels of the atmosphere. There are anumber of locations in the world wherein this condition exists due tothe fact that the prevailing wind, before passing over the arid or otherregion, passes over large bodies of water and, from natural evaporation,has a relatively high water content.

While it appears that orographic lift is the most practical means forproviding the lifting of the air mass once treated, it is conceivablethat by the use of thermal uplift conditions the air mass could beforced to rise to the level where precipitation would occur. In thisrespect, it may be possible to treat desert or arid regions in such amanner, such as by covering large portions ofthe desert surface withasphalt, other nearintrared heat absorbing and far-infrared radiatingmaterial, to

produce a thermal updraft condition downwind from the spray region whichcould be used to lift the treated air and produce precipitation.However, the most practical and economical means for raising the treatedair is through orographic lift.

In the practice of the inventive concept the spraying of the sea waterinto the air, the location at which spraying will occur and the othercontrollable variations will be under the regulation of a computer orother data assimilating and comparing apparatus and control systems fordetermining the optimum time and period oftime for injecting the seawater into the air, and determining those locations and the extent towhich injection should occur. It is envisioned that injection into theair will only occur during those times ofthe day at which the solarradiation is at its greatest, such as between 10 am. and 2 pm, and thedistance from the air treatment region to the mountain range willdetermine at which times precipitation will occur due to the treatmentofthe air in accord with the invention.

As previously mentioned, it is also envisioned that in the practice ofthe invention in those areas having a very high hydraulic head due tothe areas being substantially below sea level, that hydroelectricgeneration stations could be utilized in conjunction with the waterdistribution system to create vast quantities of electricity, and thisfact, in conjunction with the increase in fresh water and the associatedavailability of sea water salt precipitates which would be available inthe previously arid region could make the previously unusable areasofthe world productive, and capable of being effectively used foragriculture, chemical production and manufacturing, and the inventioncould be thus instrumental in reclaiming large land areas.

BRIEF DESCRIPTION OF THE DRAWING The method of the invention isdescribed in detail in the following description and the accompanyingdrawings wherein:

FIG. 1 is an elevational view of the spraying and nonspraying regions asutilized in conjunction with a mountain range of mountains or highhills,

FIG. 2 is a plan view of the layout of the spraying and nonsprayingregions in accord with the invention as shown in FIG. I, and

FIG. 3 is a graph indicating the distribution of the injected watervapor within the atmosphere occurring at the various spraying regionsand also indicates various temperature and humidity conditions at theregions.

DESCRIPTION OF THE PREFERRED EMBODIMENT Basically, the practice of theinvention comprises the utilization of solar energy to aid and increasethe rate of evaporation of sea water sprayed into the lower atmosphereadjacent the earths surface wherein the water vapor content of the airis increased and the air is carried to a downwind mountain range andfresh water is released as orographic cumuliform precipitation.

Preferably, the sea water is sprayed into the lower atmosphere in aseries of upwind parallel regions or bands generally orientedperpendicular to the prevailing wind direction and located at aridregions below sea level. The bands will preferably be of a configurationconforming to the geographic contours of the preselected downwindmountainous terrain, and the mountainous terrain, which will be used toprovide the orographic lift, must have an elevation of several thousandfeet above the elevation of the region at which the spraying of theatmosphere occurs. The resulting evaporation from subsequent downwindbands at which spraying occurs will add incrementally greater quantitiesof water vapor to the air, and also add a generous supply ofcondensation nuclei from the sea water evaporation process to theeumulatively increasing water vapor and nuclei content derived frompreceding bands. While the atmospheric humidity increases to thepredetermined design level, low-level prevailing winds will transportthe water vapor laden air to the downward mountain range which willinduce sufficicnt orographic lift to trigger convective and dynamic airmass instability and subsequent cumuliform precipitation.

Between the alternate spray bands or regions are nonspray bands orregions which permit the radiant energy of the sun and the ground toheat the moving air into which the water is being sprayed whereby theability of the air to retain water vapor increases as the air movestoward the mountain at which precipitation will occur. As the airreceives water vapor, its ability to absorb solar energy progressivelyincreases in view of the increased water vapor content in the air andthe increased heat absorption efficiency of the air imparted by thewater vapors ability to absorb radiant energy as a black body; thus, ateach band region, progressively greater quantities of radiant energy are'capable of being absorbed by the atmosphere than is being absorbed atthe preceding bands or the air surrounding the overall treatment areaitself. This increased radiant energy absorption efficiency provides thepractical means for increasing the energy content of the modified air sothat the meteorological parameter equivalent potential temperature ofthe modified air. increases and thereby promotes convective air massinstability which is a prerequisite for triggering convectivethunderstorm activity when the air mass is lifted orographically.

For the optimum practice of the invention there are several conditionswhich should be present in order to permit practical utilization of theinventive concept. These conditions are set forth below:

I. The region in which the invention is practiced should be an arid orother high insolution region having predominately clear skies during amajor portion of the year in order to provide a relatively high level ofincoming solar energy at approximately 2.25 X l0 calories per squaremile per hour to 3.37 l0 calories per square mile per hour one-half orthree-quarters that ofthe Solar Constant of 2.00 calories per squarecentimeter per minute). 2. The local arid surface region in whichspraying is to occur should be substantially below sea level. Forinstance, the invention could well be practiced in the area of the DeadSea which is l,286 feet below sea level, or in Death Valley, California,which is 276 feet below sea level. The purpose of employing theinvention below sea level is to provide sufficient hydraulic head topermit the spraying ofthe sea water into the atmosphere to occur withoutrequiring external energy systems to drive pumps or the like. 3. Liftproducing means must be conveniently located with respect to the regiondefined above. As a matter of practical utilization. high mountainsprovide the best means for raising the treated air to a height whichwill produce precipitation. Preferably, the mountain used for orographiclift purposes should be higher than 3,000 to 5,000 feet, but hills ormountain ranges of much lower elevation may be used if other favorablephysical conditions are present with respect to the natural water vaporcontent of the air, temperature, wind velocity, etc. The mountain rangesmust be located downwind from the selected land regions at whichspraying occurs, and may be miles or so from the air treatment region,and the mountains provide an immediately available source of orographiclift to the moving high moisture content air mass boundary layerproduced by the spraying and solar heating. 4. The prevailing winds overthe spraying region and toward the mountain range producing orographiclift should be relatively low, such as in the range of 5 to 15 miles perhour at atmospheric levels below 3,000 to 5,000 feet, and under 15 tomiles per hour in the higher atmospheric layers to 10,000 feet levels.Moisture dispersion and diffusion rates at wind velocities greater thanthese levels, especially'in the levels below 5,000 feet, may prevent thepractice of the invention in that the ability of the air mass toeffectively absorb sufficient solar heat to make the system practicalmight not be possible. The evaporation process will, however, tend tostabilize thermal wind velocities and thereby temper or reduce the windspeed across the spray regions and to the mountains. 5. It is desiredthat the natural water vapor content of the air being sprayed have areasonably high level, such as from 3 to 10 grams of water per kilogramof dry air in the lower atmospheric regions. By having such a naturalwater vapor content the quantity of water that must be sprayed in theair is reduced, and the apparatus and expense of operation of the systemis accord with the invention is reduced. This amount of natural watervapor is generally present, however, through out the world especiallywhen the prevailing winds traverse large bodies ofwater, such as fromthe Mediterranean Sea, prior to passing over the arid sea level region.6. Preferably, relatively hot arid surface temperatures should exist inthe land region at which spraying occurs. For instance, degrees from atleast to 70 F. in winter and at least 65 to 95 F. in summer shouldprevail. These relatively high temperatures improve thermodynamic airmass properties that complement the operational success of theevaporative process occurring during the invention, for instance, theanhydrous capacity (low relative humidity) of air mass increases, whichis the ability of the air mass to evaporate and absorb additionalmoisture. Additionally, the high temperature complements the adiabaticor evaporative cooling capacity of the air mass and thereby complementsthe degree to which the forced evaporation process occurring during thespraying can temper or lower the characteristic thermal wind velocitiesand ambient temperatures found in arid regions. Additionally, the anglelying between the dry adiabatic and saturation adiabatic lapse ratesofthe adiabatic chart becomes markedly divergent as a function of bothhigher ambient temperatures and ab solute humidity, and this factor aidsin producing conditions for absorbing and retaining water vapor. 7. Forpurposes ofefficiency, and most effective operation, the spraying of themoisture into the air to produce a forced evaporative condition shouldoccur at the time of maximum level of available solar radiant energy.Unlike a sea or other body of water, a force-sprayed evaporation systemtransforms radiant energy to latent heat of evaporation during the timeof maximum radiant energy or the peak insolation period of the day.Though the reflectivity of a body of water is low at low angles ofincidence, its transmissivity is very high in the characteristic solarradiant energy wavelengths. As a system for converting solar radiationto latent heat of evaporation on a real time ba sis, a body of wateroperates as a heat sink which recycles but once every 24 hours. For suchpurposes, it is not an efficient real time operational system and cannotbe time phased to evaporate an optimum quantity of water into theatmosphere at the time of maximum solar insolation. In contrast, aforcesprayed sea water system can function on real time basis, and aconcentrated region of water spray and resulting water vapor acts as ablack body radiant absorptive system to most wavelength regions bothsolar and earth surface radiant.

There are a number of regions in the world in which the aforementionedphysical requisites are present. For instance, in the southwestern partsof the United States there are arid desert regions below sea level, suchas in Death Valley, which could practice the invention. Additionally, inthe Dead Sea area adjacent Israel and Jordan the geographical terrain issuch as to provide excellent means for practicing the invention. Thereare desert regions of western Australia which also appear to havephysical characteristics in which the invention could be practiced. Theisland of Anegada, and the island of Malta also appear as possiblelocations for practicing the inventive concept. The Qattara Depressionof northwestern Egypt also appears to have physical characteristics inwhich the invention could be practiced. However, there is a question asto whether sufficient mountain heights areavailable to provide thenecessary orographic lift required in this particular area.

FIGS. 1 and 2 of the drawing illustrate a physical arrangement ofspraying and nonspraying regions in accord with the practice of theinvention. In these FIGS. an arid desert type land region is indicatedat 10 which is preferably below sea level. The prevailing wind isindicated by the arrow 12 and the mountain range 14 exists downwind fromthe arid region a distance of 20 miles or so having an elevationpreferably above 3,000 to 5,000 feet. A plurality of bands or regions 16and 18 are defined on the arid region 10 in a manner as will be apparentin FIG. 2. These bands are preferably substantially parallel orconcentric to each other, and are parallel or concentric with respect tothe mountain range 14 which will be providing the orographic lift. Theregions 16 are designated spraying regions or bands, and the regions 18constitute solarheating bands. The regions 16 and 18 may be ofapproximately equal width of about 1 mile with respect to the directionof prevailing winds as indicated by the arrow, and are perpendicularlyrelated to the direction of prevailing winds. The exact width of regions16 and 18 with respect to the direction of prevailing winds may varyconsiderably depending on the location of the installation and the localconditions, such as direction and velocity of prevailing winds, averagetemperatures and the like. In that a considerable number of factors areinvolved in determining the humidity, temperature and other physicalcharacteristics present at any given time it is expected that a computertype evaluating system will have to be used to control the operation ofthe nozzles.

A plurality of water injection devices 20 such as nozzles mounted atoptowers or high hills or the like are disposed in the regions 16 forspraying finely dispersed water droplets into the lower atmosphere, andthese water spraying devices are connected to a supply source, notshown, supplying a control center 22 through conduits. The controlcenter will likely inelude a computer system for analyzing the weathercharacteristics and determining optimum times and flow rates foroperation of the spraying system. Under certain conditions it may benecessary only to operate a portion of the nozzles within sprayingregions 16, or certain spraying bands or regions 16 may not be operatedat all under natural high moisture content conditions.

A catch basin or reservoir system 24 of natural or manmade origin may bedefined along the lower upwind side of the mountain range 14, or theprecipitation occurring at the mountain range may merely be allowed toseep into a porous sand or ground in order to raise the water tablelevel of the ground strata for recovery of the fresh water throughwells. In that some rainfall may occur on. the downwind side of themountain range a catch basin may also be disposed on that side of theorographic lift producing region, if desired.

FIG. 3 illustrates the moisture diffusion distribution in the air as ittravels over the spray and nonspray solar heating regions. The moisturediffusion curves indicated at 26 represent the diffusion of the watervapor introduced into the air and retained thereby during theevaporation process, and it will be noted that as the vertical lines 28represent alternate spray and nonspray regions that it takesapproximately five spray bands, or 10 miles, (though this distance willvary depending upon the prevailing wind velocity), for the water vaporto rise from the sea levels altitude to approximately 3,000 feet. As thecurves show that the water vapor vertical diffusion rate decreases as itapproaches the 3,000 foot level, the vertical rise of the curve can beexpected to level out for relatively short distances of 10 to 30 miles.

Water may be provided for the control center 22 by means of an aquaduct,channel or other transport system which is capable of handling the vastquantities of water that will be necessary. In that the preferred aridregion being sprayed is below sea level a reservoir would be employed atthe point of use above the sea level elevation for supplying the waterunder high pressure to the control center.

As an example of a thermal budget summary which may occur at the regionof the mountain 14 the cloud base may occur at 4,000 feet as indicatedat 30. Air entering the foothills of the mountain at sea level at 60 F.cools at a dry adiabatic lapse rate of approximately 5.5 F. per 1,000feet of elevation, and thus upon the air reaching the 4,000 foot cloudbase level the temperature would be 38 F. As the air continues to moveupwardly along the windward face of the mountain, the air cools at amoist adiabatic lapse rate above the 4,000 feet cloud base, at a rate of3.2 F. per 1,000 feet of elevation, assuming precipitation is occurring.Assuming the mountain to be 10,000 feet tall the temperature of the airas it passes over the mountain would be I8.8 F. As the air passes overthe mountain and descends on the opposite side it warms at a dryadiabatic lapse rate of 5.5 F per 1,000 feet, and will have atemperature of 73.8 F. at sea level. For any given region the averagetemperatures differ during the four seasons during the year, and thusthe precipitation occurring at the mountain 14 during the varyingseasons ofthe year will begin at various elevations as determined by thetemperature water vapor, latent heat and other factors affecting theconditions at which precipitation will occur.

In general, unsaturated dry air of 20 C. ambient temperature coolsapproximately 2.8 C. for each 1,000 feet of lift through the lowerlayers ofthe atmosphere. Saturated wet air under these same conditionscools at the rate of 12 C. per 1,000 feet of lift. The latent heat ofcondensation energy stored in the water vapor is released in thecondensation precipitation process and remains behind to heat the aircolumn. The quantity of heat released approximates the differencebetween the 2.8 C. and the l.2 C. lapse rates. The resulting maximumvelocity induced to the resulting vertical air column is given by theequation where v meters/second. AT =Abs. of vertical mean temperaturedifferential between the cloud and adjacent air, and T=Abs. of meanmoist adiabatic lapse rate temperature of the vertical column ofmoistair. Ascending velocities vary greatly and range from 15 to m.p.h. inrain shower cumulous to upwards of 75 m.p.h. in thunderstorms.

In the case of a high moisture content layer of air, such as thatprovided by the practice of the invention. the following comments applywith respect to this lower layer of air and the orographic lift itreceives which will help in understanding the convective instability isa potential instability state existing in a layer of air. Thisinstability generally cannot be released unless the layer is lifted bysome external force. such as orographically. As a convective unstablelayer is lifted, the lower portion becomes saturated and ascends moistadiabatically while the upper portion ascends dry adiabatically untilits condensation level is reached. The process involves considerablemixing within the layers as the result of the vertical velocityresulting from the condensation heat released by the lower portion. Thismixing causes an increase of the resulting adiabatic lapse rate untilthe upper portion becomes saturated. If, at the elevation where theupper portion of the layer becomes saturated, the resulting lapse rateis greater than the air mass surrounding, convective instability isreleased and overturning occurs. Once convective instability is releasedthe moist column of air will continue to rise automatically and draw thesurface level moist air into the rising vertical column of air.Thereafter, further orographic lift is not not required to maintain theinstability system. Thus, the system will continue to function under itsown power and release cumuloform rainfall to the desert below as long assurface or lower level moist air remains available in sufficientquantities to feed the system.

From the foregoing it will be appreciated that in view of the variousfactors which affect the production of rainfall, that computerizedcontrol of the apparatus for practicing the method of the inventionprovides the most practical means for providing efficient regulation andoperation of the apparatus. Depending upon the moisture content of air,temperature, wind velocity, and other factors, it may not be necessaryto operate the spraying nozzles in all of the bands available, and thusthe most efficient utilization of sea water can be determined in accordwith the varying weather conditions.

The diagram of FIG. 3 also includes information concerning the potentialtemperatures and humidity increase as air moves across the land region10 and is alternately subjected to the water vapor increase occurring atbands 16, and the energy increase and temperature rise occuring at bands18. The lower horizontal line which represents land level 10 withrespect to the diffusion curves 26 is also indicated as line A" and whenso designated indicates a reference line indicating changes in relativehumidity near the ground level of area 10. Lines 28 continue to indicatethe boundaries of the regions 16 and 18. As the wind moves from the leftto the right through the bands 16 and 18 it will be appreciated that therelative humidity sharply increases as the air travels over the sprayingregions 16, and lowers as the air is heated as it passes over theregions 18. The increase in relative humidity at each band 16 is greaterthan the reduction in relative humidity occurring at the bands 18 whichresult in an overall increasing of the relative humidity as indicated bythe line 30.

The horizontal line of FIG. 3 representing 1,000 feet is also designatedreference line B to designate a temperature reference located near theground level. The line 32 indicates the alternating increase anddecrease in the ambient temperature of the air as it travels over theregion 10, toward the lift producing region at the right.

In FIG. 3 the 2,000-foot reference line is also designated C forpurposes of indicating a reference line with respect to the mixing ratiowithin the lower 3,000 feet elevation. This ratio is indicated byreference line 34 and it will be appreciated that this characteristicalso increases as the air moves toward the lift producing the region.

In the previous description the introduction of the sea water into theair has been limited to a forced spray system. It is envisioned thatother means for forcing high rates of sea water evaporation into the aircould be utilized at the regions 16 other than spraying. For instance, awick system could be utilized. Alternatively, experimentation has beensuccessful in the field of increasing surface evaporation by the use ofstatic electrical charges over a body of water to induce polarityeffects, and with this type of an arrangement sea water could perhaps beintroduced into the air using this polarity effect at the regions 16. Itis also conceivable that a static field in combination with the sprayingof the water into the air, as previously described. would have potentialbeneficial effects and advantages. Additionally. the use of sea water towet sand regions could be used to-increase the rate of evaporation, as

when the spray system is in operation, although it is expected that suchsand regions, without the spray region, would have to extend overconsiderably areas.

It is appreciated that modifications to the inventive concept may beapparent to those skilled in tee art, and it is intended that theinvention be defined only by the scope of the following claims.

lClaim:

l. A method of producing fresh water by weather modification wherein aprevailing wind passes over a high solar-radiant energy flux regionbelow sea level toward an orographic elevation such as a mountain havinga height of least 1,000 feet comprising the steps of dividing the regionwindward of the mountain into a plurality of elongated bands of areasubstantially parallel to each other and disposed substantiallyperpendicular to the-direction of the prevailing wind, and spraying seawater into the lower atmosphere at alternate bands of area to subjectthe air to alternate treatments of exposure to the sprayed sea water toincrease the water vapor of the air and solar heating of the air toincrease its ability to absorb water prior to its being lifted andadiabatically cooled by the mountain to produce precipitation.

2. In a method of producing fresh water by weather modification as inclaim 1 wherein said bands of area are ofa width having a constant ratioof width between the solar-heating band and the adjacent water sprayband with respect to the direction of the prevailing wind.

3. In a method of producing fresh water by weather modification as inclaim 2 wherein said bands are of a width of approximately 1 mile in thedirection of the prevailing wind.

4. A method of producing fresh water by weather modification wherein aprevailing wind exists having a direction of movement over a highsolar-radiant energy flux region toward an air current lift-producingregion, comprising the steps of dividing the region windward of said aircurrent lift-producing region into a plurality of longitudinal bands ofarea disposed substantially perpendicular to the direction of theprevailing wind and force introducing sea water into the loweratmosphere at alternate bands of area to subject the air to alternatetreatments ofexposure to the sea water to increase the water vaporcontent of the air and thereby increase the natural .ability of themodified air to absorb radiant energy with increasing greater efficiencyas a result of the added water vapors ability to absorb radiant energyas a black body constituent of the modified air mixture and solarheating of the air to increase its ability to absorb additionalquantities of water vapor and radiant energy prior to its being raisedby the air current lift-producing region to produce precipitation.

5. A methodof producing fresh water by weather modification wherein aprevailing wind exists having a direction of movement over a highsolar-radiant energy flux region toward an air current lift-producingregion, comprising the steps of dividing the region windward of said aircurrent lift-producing region into a plurality of longitudinal bands ofarea disposed substantially perpendicular to the direction of theprevailing winds and forcibly spraying sea water into the loweratmosphere at alternate bands of area to subject the air to alternatetreatments of exposure to the sprayed sea water to increase the watervapor content of the air and thereby increase the natural ability of themodified air to absorb radiant energy with increasing greater efficiencyas a result of the added water vapors ability to absorb radiant energyas a black body constituent of the modified air mixture and solarheating of the air to increase its ability to absorb additionalquantities of water vapor and radiant energy prior to its being raisedby the air current lift-producing region to produce precipitation.

6. A method of producing fresh water by weather modification wherein aprevailing wind exists having a direction of movement over a highsolar-radiant energy flux region toward an air current lift-producingregion comprising a high orographic elevation such as a mountain,comprising the steps of dividing the windward region of said highelevation into a plurality of longitudinal bands of area of generallyarallel configuration isposed substantially perpendicu ar to thedirection of the prevailing wind and forcing sea water into the 5atmosphere at alternate bands of area to subject the air to alternatetreatments of exposure to the sea water to increase the water vaporcontent of the air and the quantity of solar energy absorbed by the airto increase its ambient temperature and reduce its relative humidity andthereby increase its ability to absorb increasing quantities of watervapor prior to its being lifted by the orographic elevation to produceconvective air mass instability, cumuliform clouds and precipitation.

7. A method of producing fresh water by weather modification as in claim5 wherein said bands of area are of a width having a substantiallyconstant ratio ofdimension between the solar-heating band and theadjacent water spray band with respect to the direction of theprevailing wind.

2. In a method of producing fresh water by weather modification as inclaim 1 wherein said bands of area are of a width having a constantratio of width between the solar-heating band and the adjacent waterspray band with respect to the direction of the prevailing wind.
 3. In amethod of producing fresh water by weather modification as in claim 2wherein said bands are of a width of approximately 1 mile in thedirection of the prevailing wind.
 4. A method of producing fresh waterby weather modification wherein a prevailing wind exists having adirection of movement over a high solar-radiant energy flux regiontoward an air current lift-producing region, comprising the steps ofdividing the region windward of said air current lift-producing regioninto a plurality of longitudinal bands of area disposed substantiallyperpendicular to the direction of the prevailing wind and forceintroducing sea water into the lower atmosphere at alternate bands ofarea to subject the air to alternate treatments of exposure to the seawater to increase the water vapor content of the air and therebyincrease the natural ability of the modified air to absorb radiantenergy with increasing greater efficiency as a result of the added watervapor''s ability to absorb radiant energy as a black body constituent ofthe modified air mixture and solar heating of the air to increase itsability to absorb additional quantities of water vapor and radiantenergy prior to its being raised by the air current lift-producingregion to produce precipitation.
 5. A method of producing fresh water byweather modification wherein a prevailing wind exists having a directionof movement over a high solar-radiant energy flux region toward an aircurrent lift-producing region, comprising the steps of dividing theregion windward of said air current lift-producing region into aplurality of longitudinal bands of area disposed substantiallyperpendicular to the direction of the prevailing winds and forciblyspraying sea water into the lower atmosphere at alternate bands of areato subject the air to alternate treatments of exposure to the sprayedsea water to increase the water vapor content of the air and therebyincrease the natural ability of the modified air to absorb radiantenergy with increasing greater efficiency as a result of the added watervapor''s ability to absorb radiant energy as a black body constituent ofthe modified air mixture and solar heating of the air to increase itsability to absorb additional quantities of water vapor and radiantenergy prior to its being raised by the air current lift-producingregion to produce precipitation.
 6. A method of prOducing fresh water byweather modification wherein a prevailing wind exists having a directionof movement over a high solar-radiant energy flux region toward an aircurrent lift-producing region comprising a high orographic elevationsuch as a mountain, comprising the steps of dividing the windward regionof said high elevation into a plurality of longitudinal bands of area ofgenerally parallel configuration disposed substantially perpendicular tothe direction of the prevailing wind and forcing sea water into theatmosphere at alternate bands of area to subject the air to alternatetreatments of exposure to the sea water to increase the water vaporcontent of the air and the quantity of solar energy absorbed by the airto increase its ambient temperature and reduce its relative humidity andthereby increase its ability to absorb increasing quantities of watervapor prior to its being lifted by the orographic elevation to produceconvective air mass instability, cumuliform clouds and precipitation. 7.A method of producing fresh water by weather modification as in claim 5wherein said bands of area are of a width having a substantiallyconstant ratio of dimension between the solar-heating band and theadjacent water spray band with respect to the direction of theprevailing wind.